Making a precision pipe with 30 deg bends
To create a precision model suitable for 3D printing here is how I finally solved the puzzle that enabled me to enter the exact dimensions and angles needed for the part. If you know all the key strokes, you only need to read the first sentence in each item. The remainder are just step by step keystrokes for those not familiar with navigating around Blender

Add mesh cylinder – and set the following


A)   Vertices = 100 B)   Radius = 29.2142
C)   Depth = 60 mm
D)  Fill Type    = Nothing
E)   After other setting
are made scale it.
Ctrl + A &gt; Scale



Add 30 loop cuts (one for each degree) for bending the pipe as follows


A)    Tab into edit mode
B)    Ctrl + R, Left Click, Right Click
C)    Enter 30 in Number of Cuts



Add Solidify modifier to cylinder wall


A)    Switch to top view press Numpad 7
B)    Click the modify tab “wrench icon”
C)    Click Add Modifier and select Solidify
D)    Change Thickness to 1.63mm
E)    Check Even Thickness and High Quality Normals (note - picture does not show these two checked, but it is needed to make both inside and outside walls even)
F)    To add to inside wall leave offset at -1. To add to outside wall change to 1
G)  Click Apply



Add an empty to use as an axis point for bending the pipe


A)    Shift + A – add empty, use type with arrows easier to see orientation of empty.
B)    Scale it up a bit so it is easier to see
C)    Move it on the Y axis about 40 mm
D)    Both the cylinder origin and the empty should be on the Y baseline



Add Simple Deform modifier to cylinder


A)    Select cylinder
B)    Click Add Modifier and select Simple Deform
C)    Select Bend
D)    In Axis, Origin select the empty you added in step 4
E)    Change angle to 30 degrees
F)    Click Apply (Important for the next step)



Change origin of pipe to the bottom


A)    Tab into edit mode
B)    Change to Edge Select mode
C)    Select either inner or outer bottom edge. Hold cursor over edge and press Shift + Alt to select the complete circle
D)    Move cursor to selected by pressing Shift + S and choose Cursor to Selected
E)    Tab into object mode
F)    Click Object and select Set Origin / Origin to 3D Cursor
G)    Move cursor to World Origin, Shift + S to World Origin
H)    Then move pipe to 3D Cursor, Shift + S Selection to Cursor




Set pipe flat on base line


A)    Change view to Right Orthographic view by clicking numpad 3 pad
B)    Turn on Snapping, make sure Increment is selected and the magnet icon is highlighted. Or with cursor in viewport open the property settings menu and type N
C)    Rotate the pipe on the X axis -15 deg.  Either typing -15 in Rotation X or in the viewport, type R then rotate pipe with mouse until it snaps to the y axis



Extrude top faces of pipe 20mm


A)    Tab to Edit mode
B)    Change view to solid mode
C)    Select Face mode
D)    With cursor over a top face select all with Shift-Click
E)    With top faces selected type E to extrude and 20 for 20mm



Duplicate pipe and rotate


A)    Tab to object mode
B)    Change to wireframe and X-ray mode
C)    Switch to Right Orthographic view, click Numpad 3
D)    Duplicate pipe with Shit+D and Enter
E)    The new pipe needs to be rotated 180 deg on X axis, BUT it is already sitting at a -15 deg angle. You can either enter -195 in the items property settings or with snap to grid still activated hold down Ctrl while rotating pipe with mouse until it snaps in place so both pipe sections match up exactly.



Prepare both pipes to be joined into one object by removing bottom faces from both pipes before joining




Switch to solid mode




Press H to hide bottom pipe temporarily




Select top pipe and Tab into edit mode




Select bottom faces as described earlier




Press X and select Delete Faces




Tab back into Object mode




Press Alt+H to reveal bottom pipe




Make sure only the top pipe is selected press H to hide




Then repeat these steps for the bottom pipe for the edge that will be joined to the top pipe





Next join both pipes with a simple Join Ctrl+J


A)    Switch to wireframe and X-ray mode
B)    Select both pipes
C)    Click Ctrl+J to join the two pipes.



Verify the final pipe can be 3D printed. This can most easily be done if the 3D-Print add-on has been installed in preferences. The main thing is the final object cannot have non-manifolded edges.  But since The posted questions really does not speak to this issue, I will not cover it in detail other than to say since the final object has to be printed, the dimensions have to be accurate or else the part would be useless